Out-of-bounds Read Affecting microvm-kernel6.18 package, versions <1:6.18.56-125.164.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.17% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-MICROVMKERNEL618-21804462
  • published29 Oct 2026
  • disclosed18 Oct 2026

Introduced: 18 Oct 2026

NewCVE-2026-98728  (opens in a new tab)
CWE-125  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 microvm-kernel6.18 to version 1:6.18.56-125.164.amzn2023 or higher.
This issue was patched in ALAS2023-2026-3251.

NVD Description

Note: Versions mentioned in the description apply only to the upstream microvm-kernel6.18 package and not the microvm-kernel6.18 package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

tpm: fix off-by-four bounds check in tpm2_get_random()

When the response carries the TPM2_ST_SESSIONS tag, tpm2_get_random() skips the 4-byte parameter size field before locating the random data, but the bounds check still validates the response length against TPM_HEADER_SIZE. A truncated response can pass the check and make memcpy() read up to 4 bytes past the response end, so stale buffer contents end up in the caller's random bytes.

Fix this by checking the response length against 'offset', which already includes the skipped parameter size field.

CVSS Base Scores

version 3.1